A pox party (also measles party, flu party etc.) is a social activity where children are deliberately exposed to an infectious disease, supposedly to promote immunity. Such parties are typically organized by anti-vaccinationists on the premise of building the immune systems of their children against diseases such as chickenpox and measles (which can be more dangerous to adults than to children) or flu. Such practices are highly controversial and are discouraged by public health officials in favor of vaccination. In the USA, if the exposure involves the United States Postal Service to swap tainted items, the practice is illegal.
Parents who expose their children to the virus in this manner may believe that this method is safer and more effective than receiving a vaccination. Similar ideas have been applied to other diseases such as measles. However, pediatricians have warned against holding pox parties, citing dangers arising from possible complications associated with chicken pox, such as encephalitis, chickenpox-associated pneumonia, and invasive . Although such complications are not common, they can cause brain damage or death. Before the chickenpox vaccine became available there were 100 to 150 deaths from chickenpox among children in the U.S. annually. All of the illnesses the parties are intended to ameliorate, including not only chicken pox, but other diseases such as mumps and hepatitis A, can be life-threatening to children if treated inappropriately. The chickenpox vaccine is recommended by health officials as a safe alternative.
Some parents have attempted to collect infected material, such as saliva, licked lollipops, or other infected items from people who claim to have children infected with chickenpox. The parents use social networking services to make contact with these strangers. The unknown person then mails the potentially infectious matter to the requester, who gives it or feeds it to his or her child in the hope that the child will become ill.